The recent emergence of Gram positive bacteria which are resistant to many current antiinfective therapies presents a challenge to the pharmaceutical industry: New classes of inhibitory molecules are needed which are substantially different than the previous generation of drugs. This need is heightened in the wake of recent occurence of Bacillus anthracis infections, and the need for additional antiinfectives to treat anthrax. Cubist Pharmaceuticals is addressing this need by using a target-based drug discovery process that centers its efforts on bacterial targets whose activity has not yet been targeted by an antiinfective. In this proposal, we present a clear-cut route for identifying leads for a broad-spectrum(B. anthracis -inclusive) antiinfective therapy through a target-based high throughput screen of bacterial Undecaprenyl diphosphate synthase (Upps).